Air Compressor Keeps Tripping Reset Button (Thermal Overload) – Solutions & Causes

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With just a couple of minutes running time, or sometimes after ten or fifteen minutes or so, the air compressor reset button always trips on my air compressor.

If this is your compressor problem, this article will provide a few things to look for and perhaps fix if your compressor reset button always trips.

Table of Contents

What’s the Purpose of an Air Compressor Thermal Overload Reset Switch?

First of all, let’s discuss the role of a compressor reset button. The compressor thermal overload reset, also commonly referred to as a thermal cut-out, thermal overload, or safety switch, is there to automatically turn off the air compressor’s power when it overheats. Learn about the basics of motor protection here!

The reset button is there to protect the motor from becoming damaged if the compressor begins overheating. That’s also why the air compressor keeps tripping the reset button because the system is becoming too hot. You can typically find the reset button on the end or side of your compressor, and sometimes even located inside the wiring of the motor.

The thermal overload button is used in series with the power supply to the motor and in the event of excessive overload or heating, it cut off power to the motor to allow it time to cool down.

Some thermal overload switches are manual, and require the big red button on them to be pressed when the air compressor has cooled. Others are auto-reset types, which automatically let the motor restart when it has cooled enough. All thermal reset switches are similar in design, regardless of what electric motor they’re on, whether that’s an air compressor, air conditioner, or heating blower. You can view some thermal reset switches here!

Where is The Reset Button & What Does it Look Like?

You might know it as the thermal cut-out or thermal safety switch. Others know it as the reset button. You can see one of them on the end of the electric motor in the image below.

Compressor Blows Motor Breaker Switch
Compressor Blows Motor Breaker Switch

It may be a small red button on the shroud of the compressor, it may be a button on the end of the motor if that is visible on your compressor, and I have seen them on the side of the motor at the shaft end, on some compressor motors.

Some are inside of the wiring cover on the motor, others are an inline switch on the wiring. The locations of this important piece of equipment on the air compressor sure do vary.

Thermal Reset button on 40400
Compressor motor reset button on one model of compressor motor
Reset button is easily visible on this compressor motor

Regardless of where the compressor thermal reset button is on your compressor – on the motor or on the shroud of the compressor – its purpose is to cut the power to the motor in the event that the motor itself gets too hot.

Without the air compressor thermal overload switch, if there were a condition in the motor that was causing it to get hot, eventually the heat itself would destroy the compressor motor.

If the compressor reset button always trips on your compressor, the motor is getting too hot and you may need a replacement. For information on how to buy a compressor motor reset switch please visit our guide!

Why a Compressor Reset Button Always Trips

There are a few reasons as to why your reset button may be tripping on your air compressor and these are:

  • The power supply
  • The compressor runs too long
  • Centrifugal switch

The Power Supply

Check to make sure that your air compressor is plugged right into the wall socket, and that it is not being powered through an extension cord or power bar. The reason being is that the wire in the extension or power bar may not be large enough to allow the flow of power that the compressor motor needs.

The power cord of the compressor is sized to allow sufficient power to the compressor motor. Restricting it through a smaller wire will cause the motor to overheat. If the motor overheats, the thermal cut-out will shut it down. This is a very common issue.

Compressor Runs Too Long

If you are using your air compressor for extended periods, more than, say, ten or fifteen minutes at a time, the typical DIY air compressor will overheat. The duty cycle of the compressor may be less than the time you are requiring it to run, and the motor will overheat. If you think this is happening to your air compressor, try only running it for ten minutes and then letting it sit for at least that time so the motor can cool, before firing it up again.

Older air compressors – and some not so old if the compressor has tipped over for some reason – can develop a tank check valve leak. If that happens, air will be bleeding out of the tank all the time, even when the compressor is running. If that is happening on your air compressor, it will take much longer for the tank to fill – if it ever does – to cut out, and the by-product of that is a motor that overheats.

See the troubleshooting pages on this site about how to fix a leaking tank check valve.

If your air compressor has or is developing a mechanical issue – perhaps a weakened or broken intake or pressure valve or a blown gasket in the pump, the compressor may have to run much longer than normal to fill the tank to cut out.

It may run so long that the motor will shut down on thermal cutout before the tank is full. If your air compressor seems to be undergoing this scenario, it may be time to add a valve and gasket kit. The troubleshooting pages hyperlinked on this page address these issues.

Centrifugal Switches

Our thanks to Waite Mccormick for providing the following information on centrifugal switches and their role in thermal overload:

Another issue, the centrifugal switch can stick which will keep the start windings energized tripping the thermal switch within 30 sec.

Centrifugal Switch

That centrifugal switch is kinda like 1st gear sorta speaking, and when the motor gets almost 3/4 of its design RPM, it shifts the motor windings to the run windings, kinda like a running drive gear.

The start windings are much smaller and can’t withstand the heat (of running full rpm) and resulting in the kicking of your thermal overload. Over time, the centrifugal switch can shift out of adjustment, causing it to get stuck in a singular position.

If the centrifugal switch were to get stuck in an open position then the windings won’t shift properly. The start windings can’t withstand the heat of the compressor’s full RPM which subsequently causes the compressor to overheat.

How to Stop Your Air Compressor Reset Button From Tripping

I’ve provided you with the 3 reasons why your air compressor reset button keeps tripping. Now, let’s focus on ways to combat this!

Time needed: 10 minutes.

Air Compressor Reset Button Fixes

  1. Fixing Power Issue

    Make sure that the air compressor is plugged directly into a wall outlet that provides 20 amps or more, and do not use power bars or extension cords.

  2. Fixing Running the Compressor for Too Long

    To not overwork the air compressor, or exceed its duty cycle, Run the compressor for say 10 minutes, and then allow it to sit for 10 minutes before running it again. This will allow the engine sufficient time to cool and ensure that it doesn’t overheat and trip the reset button.

  3. Fixing a Sticking Centrifugal Switch

    First of all, you want to make sure the points on the contact plate are in the open position by bending the circular spring flat so the points are no longer in contact. If the points are welded shut, the contact plate needs to be replaced. If there is light pitting on the surface points, you should be able to sand them gently with say 400 grit sandpaper. Anything larger will create an unstable condition and so, the contact plate must be replaced.

Air Compressor Reset Button Tripping Fix YouTube Demonstration

I have picked out the below video as a useful YouTube demonstration on how to fix your air compressor reset button.

What to Do if You Think Your Air Compressor Thermal Overload Switch Is Faulty?

What are your options if it turns out that your thermal overload switch is faulty, and tripping when the compressor isn’t overheating? In this situation, you’re probably better off buying a replacement than trying to DIY fix the switch. I’d first recommend seeking professional advice, whether that is at a repair center or a local compressor store.

Air Compressor Tripping Thermal Reset Button vs Tripping Circuit Breaker

People often confuse tripping the thermal reset button and tripping the circuit breaker. The key difference is that the thermal reset button is solely due to overheating while the circuit breaker is down for a number of reasons. If the motor on the air compressor is unable to start for whatever reason, but still tries to draw power, it may exceed the amperage and capacity of the breaker, causing it to trip.

Circuit breakers are likely to trip due to air filters, broken extension cords, clogged cylinders, faulty pressure switches, failed capacitors, failed unloader valves, and more. For more information visit our Air Compressor Keeps Tripping Circuit Breaker – Why & How To Fix guide!

FAQs (Frequently Asked Questions)

Why does my compressor keep tripping out?

It is likely that your compressor is tripping due to your power supply not being large enough to power the compressor or the compressor is overheating from working for too long and so the reset button trips.

Where is the reset button on my compressor?

The reset button can be located on the motor or the shroud of the compressor, it typically depends on the make and model of your compressor.

Where is the reset button on a air compressor?

It really does depend on the make and model of the compressor. Some compressors will have their reset buttons wired into the motor, whilst others are located at the end of the compressor.

Do air compressors have a reset button?

Reset buttons, otherwise known as thermal switches or thermal reset buttons, are important parts of air compressors as they ensure that air compressors do not overheat to prevent damage to parts and the overall system.

How do you reset an air compressor?

Look for the reset switch, typically a small red or black button near the side of the motor near the power cord, and click this. The location will vary depending on the make and model.

Why do I have to keep resetting my air compressor?

The sole purpose of resetting your air compressor is that it is getting too hot. Therefore it cuts power to the compressor to ensure that it doesn’t overheat any further and subsequently prevent damage from occurring.

Existing Reader Reset Button Tripping Problems and Responses

Harbor Freight Compressor Thermal Switch Keeps Popping Out


I have the 90234 air compressor from harbor freight. I have used it quite often for over a year. I have even pushed it on multiple occasions running it nonstop for hours without a break.

Yesterday while using it with my sandblaster the air compressor thermal overload switch popped and the compressor died.

Harbor Freight 90234 air compressor
Harbor Freight 90234 air compressor

I restarted it to only have it run for about thirty seconds before it died again.

Figuring it needed a rest I left it alone. Today I went to start the compressor only to have it run for another thirty or so seconds and just cut out, it didn’t even fill the tank.

The oil and its level seemed fine.

Is it possible my motor is dying? I have it on a power strip all by itself connected to an outlet without anything else and I never had this problem before even when running the compressor for hours at a time.

I am going to check tomorrow if there is a restriction of some sort on the copper line. If I can get any advice I appreciate it. Thanks


Scott, I don’t know what the Duty Cycle of your model of Harbor Freight compressor is. If you are not sure what I mean by Duty Cycle, see the page of that name linked from the sitemap page for complete info.

I think, reading between the lines, that you know that you have abused the compressor. If, in fact, it is not a continuous-duty compressor, from your own admission, you have run it long and hot, and I suspect, this has damaged your motor, if not the pump.

Sounds like you have had your money out of this one, and since, I suspect, replacing the motor may only solve one of the issues, it may be time to retire this one for parts and get another.

To be sure, find an electric motor rebuild shop, and take the motor there for a load test.

Cheers and good luck.

Here are a number of existing reader problems and helpful responses to reset button problems with various brands of air compressors:

If you have any questions regarding air compressor reset buttons then, leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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Hyundai has a wide range of air compressors in the current line-up, covering home use, DIY and professional use. There are five types of air compressors in the series, 12v DC, Silent Oil-Free, Direct Drive, Belt Drive Electric and Belt Drive Petrol engine powered.

Mine keeps kicking out on start up until it’s gets warm enough even when compressor is in room 50 degrees F

I have a little power pal air compressor I’ve been airbrushing with. Lost all air all of sudden, motor still runs a little weaker but no air. Don’t knov why

I have a Dewalt MK 246 air compressor that trips the reset button when I turn it on and the temperature is below about 40 deg. It will run very slow for about 4 seconds and trips. I have learned to run it for about 3 seconds and turn it off. Wait a few seconds and turn it back on for another 3 seconds and repeat this a half dozen times and It will eventually speed up keep running. I changed the oil from 40wt to 30wt non-detergent without any improvement. I see on a post suggesting going to 20wt… Read more »

Not sure exactly what you have, as mk 246 shows me D55153 on a search.
Given the oil chagce and no improvement, you may have a bad start cap or start contact.

I have a DeWalt model D55151 compressor and the thermal overload trips when the compressor tries to start when cold, that is below 8 degrees centigrade. Works fine if warmer. Has anyone got the answer?

Lower viscosity oil.
Presumably, it comes with 40 weight. Try 30w for cold weather.
There’s a chance the unloader sticks when cold, but try the oil first.

Last edited 2 years ago by Doug in

HI Doug,
Thank you for the information you posted. I am going to service the whole compressor in the next week or two. I have some Powermate 018-0060CT synthetic air compressor oil as it is supposed to be better for starting in colder weather. I will see if it does what it states.
Thank you

I’m fairly certain that’ll do it. Let us know how it goes…

Reference: Brenda Kronstain
Reply to  Doug in
November 30, 2020 7:21 am

I have an EmGlo airmate 1 1/2 hp that does the same thing. Can’t find a model number on it.

Brenda, please send a couple pix of it.
Also, tell what of the above checks you have performed, and the results.

Upright craftsmen compressor will start and run once’s it shuts off you have to hit the reset in order for it to start same thing will happen over and over

What model?
Does it *try* to restart? Or is the reset already tripped after it stops?

I have an EmGlo airmate 1 1/2 hp that does the same thing. Can’t find a model number on it.

Ron, if you can’t find a model, please send a couple or three pix of it
Also, please check the things mentioned above, and what you found.

Last edited 2 years ago by Doug in

I’ve had my central pneumatic air compressor for approximately 3 years I believe. I got it in the summer. I’ll have to admit it would lock up right on startup when the compressor was sitting idle and cooled off maybe three times a month. I did as recommend as far as preventive maintenance changing oil and always emptying out moisture out of tank it’s never overheated once the 3 years I’ve had it. One main complaint I’ve had ever since I bought it when it turned cold it trips the thermal switch in which the motor sounds like the valves… Read more »

I’d try 20w first, but did you read this?

Cold Weather Operation
Premium quality 30-weight, non-detergent air
compressor oil (sold separately) is recommended
for use with this compressor. Start compressor
in heated area if outdoor temperatures drop
below 32° F. If this is not practical, drain out the
old pump oil and use SAE 10W Non-detergent Air
Compressor Oil in the pump crankcase instead
whenever the compressor’s temperature will fall
below 40°. Do not use multi-viscosity oil (such
as 10W-30), they leave carbon deposits on pump
components and lead to accelerated failure. Heavy
operation may require heavier viscosity oil.

I have an 80 gallon Kobalt air compressor that I bought used. The contacts were bad so I changed out the pressure switch. I changed the oil in it also. I started it several times, ran as long as maybe a minute with valve open. The next day, I installed a shutoff valve and started it and when it got to about 25 psi after less than 30 seconds I turned it off. When I turned it back on, it would barely turn and I guess the thermal switch tripped. What would cause this?

And 90 minutes later it still won’t come on.

Ok. I didn’t realize I had to push so hard to reset so yes it is running again but the original question still remains.

Have you checked the things mentioned above on this page?

If that doesn’t lead to a fix, try here:

Let us know what you find, please.

Hi there, in less than a month, I have replaced also 3 reset switches even I bought the expensive one and it is tripping around 50 degree Celsius and the Engine and the motor is also around 50-60 degree Celsius. When I turn on I cannot find any issue but suddenly it pops out. Have replaced many n same results. I am too frustrated with this. What should I do now?

The thing to do now is to tell us what machine you are working on.

I have a Campbell Hausfeld that never gets up to full pressure before kicking out. After it kicks out, I can leave it plugged in indefinitely, and it will not comeback on. It actually needs to be power cycled for at least 30 seconds to come back on.

I know it isn’t the pressure switch, as it will do it at any pressure level, and if I bypass the pressure switch, it still cuts out below the specified 125 psi. And still needs to be unplugged for at least 30 seconds to come back on.

Any idea?

Yes. Magnetic circuit breaker either in or on the motor (electro-magnet holds it tripped until power cycle to prevent repeated restarts if unattended).
Got a model number?

Yeah, it’s a Campbell Hausfeld HL550100. I found the manuals and parts diags from their site. Looks like it is equipped with a thermal overload protection circuit. Although there isn’t much in the Manual about it, I can see it is nowhere on the parts diagrams, so that tells me it is incorporated into the motor unit. It does say to check for a bad check valve ( valve is good) and that it can be tripped because of a bad air filter. I guess off to the basics for me.. Failing that, I will look at the electrical circuit… Read more »

It’s not necessarily thermal. Could be current sensitive, too. Which might point at that (probably) run capacitor.

Have fun and good luck.

I have a 80 gallon 5hp devilbiss compressor. It works great only sometimes when it goes to restart and do another cycle it won’t and I have to hit the reset button . It’s intermittent and after I do hit the rest it will run until it gets at the right sir pressure .i have also seen sparks come from reset switch when it’s cold
Should I be replacing the reset switch as a first attempt to fix this issue ? Thanks

Maybe. Depends.
What happens between the time it goes to refill the tank and the breaker tripping?
Have you checked all the stuff in the text above? What did you find?

Will a breaker that’s too big cause the thermal reset to trip

No, but a cord too small can…Or an overloaded outlet…or just running it too hard (long running).

Last edited 2 years ago by Doug in

husky air compressor keeps tripping the reset button. I replaced the pressure switch as per the instructions. Started the compressor after replacing the switch and it trips the reset button as it try’s to reach operating pressure. It trips constantly, and can’t regulate the pressure settings.Motor doesn’t get hot.Could it be a faulty circuit breaker reset button?

“It trips constantly, and can’t regulate the pressure settings.”

Is that why you replaced the pressure switch?

“Motor doesn’t get hot.Could it be a faulty circuit breaker reset button?”

Yes, especially if you’ve been running it with an extension cord.

If you haven’t already, read this:

What model is this unit? “Husky” is a pretty broad category…

I have a Rolair VT25BIG portable air compressor. It’s used and I picked it up dirt cheap. It turns on and then the Reset Button keeps tripping, the motor does feel warm. I haven’t tried to run it for long periods, because it keeps tripping the reset button AND I don’t want to cause any damage. I’m not sure if maybe it could be the oil needs swapping, which I will be doing. Or what could be the issue. Any help fellas?

A good place start would be here:

Let us know what you find.

Dont forget centrifical switch … Thank you Waite. Your post has been added to the bottom of this main page. I appreciate your expertise.

Hello, I recently picked up a used Central Pneumatic 92504. The wire end was bare so wired it up a 220v plug and plugged it in to a 30A breaker circuit. The first thing I noticed was the motor starting a little slow, then it would surge while it ran for about 10 seconds and finally tripped the thermal breaker on the motor. I reset it a few times with the same results. I think my wiring of plug is correct and the motor and pump both freely spin the way the should, so Im guessing either the compasitors are… Read more »

You should probably verify the pressure switch actually has 220 or so V. If so then yeah, check the caps.

Will only run for two or three min it will pressure up to fifty and pop the rest button

What is “it”?
What have you checked? Any of the things above? What?

I have a campbell hausfeld it fills up but when it shuts off when it fills the tank its tripping the reset button on the motor. What will be causing this

Good question, and asked often, Brian. There’s a page about this very subject linked from the troubleshooting page on this site, and there are things to check noted there. After you review the page(s) relating to this subject if you still have compressor issues, do please add a comment telling us what’s what. Thanks.

I am attempting to replace a motor overload reset(red button on front of motor) I have three wires coming out of the motor. Blue, orange, and black of course. The is not available but the blue and black are. However there are three tabs on the back in the button. What am I missing here? Thanks for any help here!

How ’bout a couple pix of what you have? Wires, old and new breakers.

I have a Central Pneumatic 2.5 hp 22 gal vertical oil bath compressor. It runs for 30 seconds and then pops the reset button. The power supply is 12ga. solid wire on a 20 amp breaker less than 2 feet from the recep to the breaker, It does not run long enough to get hot and it is fairly new. I was told by an electric motor rebuild company here in town that it most likely is not the capacitor as it would not start if it was, he said it would just hum….

Is this a 61454, 62803, 63635, or something else?
Read the reviews. Bought in march-july this year?
Take it back for a refund. Or see if you can get one of the other ones.
If it’s too late for refund, check the capacitor anyway.
Will it get to cut-off on an empty tank? If so, you might just have a bad check valve.

Good luck.

Compressor only runs for a couple of seconds before tripping the reset button

What have you checked? Any of the items mentioned above?
A make and model might be helpful, too.

Compressor runs for about 6 or 7 seconds and trips circuit breaker. Plug is good. Wires good. Dosen’t run long enough to get hot. NO air in tank. What’s causing this?
Central pneumatic 2.5hp, 21 gallon tank.

What model? There are several

Gday I have a gen tech doing the same thing runs for a few seconds up to say 20 then cuts out flick switch and it runs for a few more then cuts out again